<template>
  <el-dialog
    width="500px"
    title="员工导入"
    :visible="showExcelDialog"
    @close="$emit('update:showExcelDialog', false)"
  >
    <el-row type="flex" justify="center">
      <div class="upload-excel">
        <input
          ref="excel-upload-input"
          class="excel-upload-input"
          type="file"
          accept=".xlsx, .xls"
          @change="upload"
        >
        <!--  拖拽中
          @dragenter 拖拽进行  容器内
          @dragover  拖拽中  持续的过程
          @drop      拖拽松手
          @dragleave  拖拽移出

         -->
        <div class="drop" @dragenter="dragenter" @dragover="dragover" @drop="drop">
          <i class="el-icon-upload" />
          <el-button type="text" @click="downloadTemplate">下载导入模板</el-button>
          <span>将文件拖到此处或
            <el-button type="text" @click="handleClick">点击上传</el-button>
          </span>
        </div>
      </div>
    </el-row>
    <el-row type="flex" justify="end">
      <!-- update:props属性名，值 直接修改 .sync修饰符的属性值 -->
      <el-button size="mini" type="primary" @click="$emit('update:showExcelDialog', false)">取消</el-button>
    </el-row>
  </el-dialog>
</template>
<script>
import { reqGetTemplate, reqUploadExcel } from '@/api/employee'
// 这种是直接解构处理
import { saveAs } from 'file-saver'
export default {
  props: {
    showExcelDialog: {
      type: Boolean,
      default: false
    }
  },
  methods: {
    // 下载导入模板
    async downloadTemplate() {
      const blob = await reqGetTemplate()
      saveAs(blob, '员工导入模板.xlsx')
    },
    // 为按钮绑定点击事件 触发文件域的点击事件
    handleClick() {
      this.$refs['excel-upload-input'].click()
    },
    // 文件域的change事件  做上传操作
    async upload(e) {
      // 1.非空处理
      if (!e.target.files[0]) return
      // 2.记录上传文件对象
      console.log(e.target.files[0])
      const file = e.target.files[0]
      // 3.处理formData类型
      const fm = new FormData()
      fm.append('file', file)
      // 4.发生请求
      try {
        await reqUploadExcel(fm)
        // 5.关闭对话框
        this.$emit('update:showExcelDialog', false)
        // 6.重新渲染
        this.$emit('reload')
      } finally {
      // 清空文件域的value(解决选择同一个文件不会触发change的问题)
      // 不管成功和失败都要清空文件
        this.$refs['excel-upload-input'].value = null
      }
    },
    // @dragenter 拖拽进行  容器内
    dragenter(e) {
      e.preventDefault()
      e.stopPropagation()
      console.log('拖拽进入了')
    },
    // @dragover  拖拽中  持续的过程
    dragover(e) {
      e.preventDefault()
      e.stopPropagation()
      console.log('dragover,持续触发')
    },
    // @drop      拖拽松手
    drop(e) {
      // 获取上传的文件对象
      e.preventDefault()
      e.stopPropagation()
      // console.log('放手了')
      this.sendFile(e.dataTransfer.files[0])
    },
    // 发送上传的请求封装
    async sendFile(file) {
      // 3.处理了formdata类型
      const fm = new FormData()
      fm.append('file', file)
      // 4.发生请求
      try {
        await reqUploadExcel(fm)
        // 5.关闭对话框
        this.$emit('update:showExcelDialog', false)
        // 6.重新渲染
        this.$emit('reload')
      } finally {
      // 7.不管成功和失败都要清空文件
        this.$refs['excel-upload-input'].value = null
      }
    }

  }
}
</script>

<style scoped lang="scss">
    .upload-excel {
      display: flex;
      justify-content: center;
      margin: 20px;
      width: 360px;
      height: 180px;
      align-items: center;
      color: #697086;
      .excel-upload-input {
        display: none;
        z-index: -9999;
      }
      .btn-upload,
      .drop {
        border: 1px dashed #dcdfe6;
        width: 100%;
        height: 100%;
        text-align: center;
        line-height: 160px;
        border-radius: 8px;
        display: flex;
        flex-direction: column;
        justify-content: center;
      }
      .drop {
        line-height: 40px;
        color: #bbb;
        i {
          font-size: 60px;
          display: block;
          color: #c0c4cc;
        }
      }
    }
</style>
